Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 207 · 40 questions

How to do it in your head (Round up, add back): Round the number you take away up to the next ten or hundred: 297 → 300 (3 too many). Take away the round number. Add back the extra, because you took away too much.

1. 1.816 − 697 =
2. 2.695 − 399 =
3. 3.674 − 299 =
4. 4.587 − 538 =
5. 5.872 − 347 =
6. 6.894 − 328 =
7. 7.713 − 119 =
8. 8.961 − 599 =
9. 9.384 − 299 =
10. 10.844 − 299 =
11. 11.615 − 549 =
12. 12.318 − 199 =
13. 13.701 − 529 =
14. 14.899 − 597 =
15. 15.863 − 397 =
16. 16.858 − 597 =
17. 17.723 − 598 =
18. 18.842 − 377 =
19. 19.640 − 299 =
20. 20.707 − 399 =
21. 21.761 − 698 =
22. 22.715 − 497 =
23. 23.879 − 697 =
24. 24.704 − 599 =
25. 25.631 − 599 =
26. 26.450 − 128 =
27. 27.616 − 199 =
28. 28.967 − 397 =
29. 29.929 − 798 =
30. 30.637 − 558 =
31. 31.573 − 498 =
32. 32.597 − 129 =
33. 33.289 − 198 =
34. 34.444 − 267 =
35. 35.581 − 408 =
36. 36.283 − 197 =
37. 37.505 − 469 =
38. 38.865 − 598 =
39. 39.820 − 698 =
40. 40.987 − 487 =

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